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| author | Andrey Konovalov <andreyknvl@google.com> | 2021-01-23 21:01:43 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2021-01-24 10:34:52 -0800 |
| commit | acb35b177c71d3d39b9a3b9ea213d926235066e3 (patch) | |
| tree | 7adcdf67da5b2f3b10fe3d310cfcfc8f1e167923 | |
| parent | ce5716c618524241a3cea821e18ee1e0d16f6c70 (diff) | |
| download | linux-acb35b177c71d3d39b9a3b9ea213d926235066e3.tar.bz2 | |
kasan, mm: fix resetting page_alloc tags for HW_TAGS
A previous commit added resetting KASAN page tags to
kernel_init_free_pages() to avoid false-positives due to accesses to
metadata with the hardware tag-based mode.
That commit did reset page tags before the metadata access, but didn't
restore them after. As the result, KASAN fails to detect bad accesses
to page_alloc allocations on some configurations.
Fix this by recovering the tag after the metadata access.
Link: https://lkml.kernel.org/r/02b5bcd692e912c27d484030f666b350ad7e4ae4.1611074450.git.andreyknvl@google.com
Fixes: aa1ef4d7b3f6 ("kasan, mm: reset tags when accessing metadata")
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Marco Elver <elver@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Branislav Rankov <Branislav.Rankov@arm.com>
Cc: Kevin Brodsky <kevin.brodsky@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/page_alloc.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 85ecaa6d0d06..783913e41f65 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1207,8 +1207,10 @@ static void kernel_init_free_pages(struct page *page, int numpages) /* s390's use of memset() could override KASAN redzones. */ kasan_disable_current(); for (i = 0; i < numpages; i++) { + u8 tag = page_kasan_tag(page + i); page_kasan_tag_reset(page + i); clear_highpage(page + i); + page_kasan_tag_set(page + i, tag); } kasan_enable_current(); } |